phosphorus metabolism and the processes of storage and transfer of energy; 

 protein and nitrogen metabolism, including nitrogenous comoounds charac- 

 teristic of aquatic animals; and lipid metabolism, including fatty acid 

 composition. Y/here possible, the information is summarized in figures 

 along the lines of conventional metabolic maps. 



The presentation of compositional analyses and physiological data 

 of aquatic animals is not the concern of this review except in a general 

 sense where it indicates metabolic pathways and possible unique processes 

 occurring in aquatic animals; tables and charts giving such information 

 have not been included. Many excellent reviews are available where this 

 type of information has been collected, and a few of them might be mentioned 

 here. A recent book giving extensive coverage of the subject, for example, 

 is The Physiology of Fishes by Brown (1957)» In a symposium on the bio- 

 chemistry of fish (TTilliams 1951) are reviews of "The Proteins of Fish" 

 by Hamoir, "The Chemistry and Metabolism of the Nitrogenous Extractives 

 in Fish" by Shewan, and "The Chemistry and Metabolism of Fats in Fish" by 

 Lovern. Hamoir (1955 a) has made an intensive review of fish proteins, 

 including enzymes, respiratory pigments, and contractile proteins 



This review is similar to those in an Annual Review of Biochemistry. 

 It is exhaustive to the point of not missing important research on the 

 intermediary metabolism of aquatic animals, but it does not cite all the 

 work done in this field. By limiting the review to appropriate enzyme 

 researches, it is found that very few enzyme researches of major interest 

 in the present problem were completed before 19U5» The survey of litera- 

 ture pertaining to this review was completed in February 1958. 



CARBOHYDRATE METABOLISM 



The study of carbohydrate metabolism in fish has been confined 

 mainly to conroositional analyses of fish tissues and eggs. Evidence 

 defining the processes involved in this phase of metabolism is indirect 

 and, for the most part, has been inferred from changes in amounts of 

 total carbohydrate, glycogen, -and glucose in relation to various physio- 

 logical and environmental factors. Little has been done to characterize 

 the specific enzyme systems and the pathways relating the intermediate 

 products of carbohydrate metabolism. 



Immers (1953) followed glycogen metabolism in the stickleback and 

 minnow by measuring changes in glycogen distribution in the liver, gonads, 

 and skin, with regard to sex differentiation and the sexual cycle. In 

 the prespawning salmon, the examination of glycogen mobilization indicates 

 that gluconeogensis (the transformation of endogenous fat and protein to 

 carbohydrate) must occur in order to meet the energy demand required during 

 migration (Fontaine and Hatey 1953). This process must occur extensively 

 in order to account for the relatively high level of sugar in the blood 

 and the more or less constant reserve of glycogen maintained by these iisn 

 during the period of fasting incident to migration, In mammals, the pr° cess 

 of gluconeogensis is dependent upon the pituitary growth hormone (Bishop 

 195U), and evidence indicates that the same holds true f or fish (Brown 

 19571. In the fasting eel that has been previously hypophysectomized, 



